Scheduling the cleaning actions for a fouled heat exchanger subject to ageing: MINLP formulation

This paper addresses the problem of scheduling the cleaning actions of a heat exchanger undergoing fouling and ageing. The existence of two discrete layers leads to the use of two cleaning methods which differ in their ability to remove the aged layer. A mixed integer nonlinear programming (MINLP) model is presented and solved for three case studies with different ageing rates. The optimal schedule consists of: (i) the timing of the cleanings and (ii) the cleaning mode in each instant.

► The heat exchanger cleaning scheduling problem is revisited.
► Two cleaning methods are available with different cost and effectiveness.
► Ageing determines cleaning effectiveness.
► A new MINLP model is presented including these aspects.
► Results for a single heat exchanger show patterns called super-cycles.